--  @testpoint:opengauss关键字returns(非保留)，作为函数名
--关键字不带引号-成功
drop function if exists returns;
create function returns(i integer)
returns integer
as $$
begin
    return i+1;
end;
$$ language plpgsql;
/
--清理环境
drop function returns;

--关键字带双引号-成功
drop function if exists "returns";
create function "returns"(i integer)
returns integer
as $$
begin
    return i+1;
end;
$$ language plpgsql;
/
drop function "returns";

--关键字带单引号-合理报错
drop function if exists 'returns';
create function 'returns'(i integer)
returns integer
as $$
begin
    return i+1;
end;
$$ language plpgsql;
/

--关键字带反引号-合理报错
drop function if exists `returns`;
create function `returns`(i integer)
returns integer
as $$
begin
    return i+1;
end;
$$ language plpgsql;
/